In recent years, a vehicle-mounted illumination device using a high intensity discharge lamp (HID lamp) as a light source becomes widespread. The vehicle-mounted illumination device is required to instantaneously start or restart the HID lamp. In general, the vehicle-mounted illumination device includes an ignitor (starter) for generating a high-voltage pulse when starting the HID lamp and an inverter for stably lighting up the HID lamp. Along with the tendency of size reduction, there is available an HID bulb in which an HID lamp and an ignitor are one-piece formed with each other. The HID bulb of the type including an ignitor one-piece formed therewith does not require a voltage of several tens kV as required in a conventional HID lamp and can be turned on and driven with an applied voltage of about 100 V. For that reason, a connection cable provided with a fitting-type connector, which is connected to a typical 12V halogen lamp, is used in connecting the HID bulb to a circuit unit having an inverter and so forth (see, e.g., Japanese Patent Application Publication No. 2010-73490).
The connection cable of this type is shown in FIGS. 9A through 9C. The connection cable 101 is connected to an HID bulb 102 in which an HID lamp 111 and an ignitor 112 are one-piece formed with each other. The connection cable 101 includes a direction-setting member 106 for coupling a cable-side connector 103 and a cable body 104 together. In the connection cable 101, the cable body 104 is arranged to extend in a direction perpendicular to the insertion direction of the cable-side connector 103. The positional relationship between the cable-side connector 103 and the cable body 104 is maintained by the direction-setting member 106 (see FIG. 9A). The direction-setting member 106 includes a claw portion 163 caught in a locking hole 123 formed on the outer circumferential surface of a bulb-side connector 122 of the HID bulb 102 and a lever 161 for lifting up the claw portion 163. The lever 161 is biased in such a state that the end portion thereof opposite to the end portion making contact with the claw portion 163 is lifted upward (see FIG. 9B). If the lever 161 is pushed down against the biasing force, the end portion making contact with the claw portion 163 is lifted up, thereby pulling the claw portion 163 upward (see FIG. 9C). In other words, the bulb-side connector 122 and the connection cable 101 can be detached by pushing the lever 161 downward and disengaging the claw portion 163 from the locking hole 123 formed on the outer circumferential surface of the bulb-side connector 122.
In the connection cable 101 disclosed in Japanese Patent Application Publication No. 2010-73490, however, the lever 161 is kept in a lifted state when the connection is locked. Thus, the lever 161 protrudes outward around the connection region. For that reason, it becomes impossible to secure a space for arrangement of other wiring members. It is sometimes the case that other wiring wires are caught by the protruding lever 161, consequently hindering a wiring work. If the lever 161 is made short, it becomes difficult to apply a leverage force. This makes it difficult to lift up the claw portion 163. On the other hand, if the biasing force of the lever 161 is reduced so that the lever 161 can be pushed down with ease, the claw portion 163 may possibly be disengaged from the locking hole 123 by a vibration or a small impact. It is therefore likely that the connection cable 101 is easily detached from the bulb-side connector 122.
Hooke-shaped protrusion portions for gripping the cable-side connector 103 and the cable body 104 are formed in the direction-setting member 106 at the opposite lateral sides of the lever 161. Thus, the lever 161 is formed of a thin rod-like member to have a reduced arrangement area. For that reason, a worker wearing gloves often feels it difficult to push down the lever 161. This makes it impossible to attach and detach the connection cable with ease.